The present invention relates to an electric motor having a spherical rotor, which is available for driving an optical sensor, a control moment gyro, an inductive detector device or an electromagnetic wave transmitter of an aircraft, a flying object or the like, or a visual sensor of a robot.
As an electric motor having a spherical rotor in the prior art, a "spherical surface motor" which is representative of multi-freedom electric motors is disclosed in Laid-Open Japanese Patent Specification No. 62-221856 (1987). This motor comprises, as shown in FIG. 16(a), a hemispherical rotor 103 consisting of permanent magnets 101 or of permanent magnets 101 and yokes 102, a stator 105 having a plurality of windings 104 arrayed on a hemispherical surface, and a spherical bearing 107 for rotatably supporting an output shaft 106 extending from the stator 105. As shown in FIG. 16(b), a driving torque in any given direction is generated by controlling a current flowing through the respective windings 104 of the stator 105 in a magnetic field produced by the permanent magnets 101 whose N-poles and S-poles are arranged along the surface of the hemispherical rotor 103.
In the "spherical surface motor" which is representative of multi-freedom electric motors in the prior art, the angle over which a rotor shaft can be swung is small due to structural limitations, the number of movable parts is many, its operating mechanism is complex, and the space within the rotor is small.